JP4288710B2 - Auto focus camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic focus adjustment camera that performs focus adjustment by detecting a focus adjustment state of a photographing lens.
[0002]
[Prior art]
2. Description of the Related Art There is known an automatic focus adjustment camera that detects a focus adjustment state of a photographic lens and performs focus adjustment by driving and controlling the photographic lens according to a detection result.
[0003]
[Problems to be solved by the invention]
However, the conventional autofocus camera does not include a storage device that stores correction data for correcting the control parameters used for lens drive control according to the lens type. There is a problem that the lens cannot be driven and controlled with various control parameters.
Further, even if a storage medium for storing correction data for correcting the control parameter according to the type of lens is provided, it is a storage medium that cannot be additionally written. There is a problem in that correction data for optimal control parameters cannot be written.
Further, there is a problem in that correction data for control parameters cannot be corrected due to lens differences or aging even for lenses of which correction data is already stored in the storage medium.
[0004]
An object of the present invention is to correct a lens drive control parameter to an optimal value in accordance with the type of lens, individual differences, or aging.
[0005]
[Means for Solving the Problems]
(1) The invention of claim 1 has lens-specific identification data and is interchangeably mounted on the camera body, drive control means for driving and controlling the lens mounted according to a drive control amount, Correction data for correcting the drive control amount according to the attached lens, including data for correcting the steady delay of the lens when driving a lens while tracking a moving subject and the delay proportional to the drive speed Is stored in the storage means based on the identification data input by the input means, the input means for inputting the identification data, and the storage means capable of writing correction data for the new lens attached to the camera body. Search means for searching for correction data and reading correction data corresponding to the mounted lens, and the correction data read by the search means. Correction means for correcting the dynamic control amount, and the drive control means drives and controls the mounted lens based on the drive control amount in which the steady delay of the lens and the delay proportional to the drive speed are corrected by the correction means. To do.
(2) The auto-focusing camera according to claim 2 is configured to identify the type of lens by unique identification data.
(3) The automatic focusing camera according to claim 3 is configured to identify individual lenses of the same type of lens by using unique identification data.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows the configuration of one embodiment.
The lens 1 is configured to be interchangeable with the camera body 2, and various types of lenses 1 can be attached to the camera body 2. The lens 1 includes a lens ROM 1A that stores unique identification data. This unique identification data is data for identifying the type of lens, or data for identifying individual lenses even if they are the same type. Alternatively, when various characteristics change due to aging, the aging of various characteristics of the lens can be dealt with by replacing the ROM with a ROM that stores new unique identification data.
The lens communication device 3 inputs lens identification data from the mounted lens 1.
[0007]
The storage device 4 is a writable memory, and correction data for correcting lens drive control parameters is stored in association with lens identification data. Note that the storage device 4 has a spare storage space for writing correction data for a new lens. Even when the same type is used, the storage device 4 stores new correction data due to lens differences, or changes in lens characteristics over time. The correction data can be written when the correction data is newly stored in accordance with the change. The lens drive control parameters are set in advance and stored in the storage device 4.
The CPU 5 searches the correction data in the storage device 4 based on the identification data of the mounted lens 1 input by the lens communication device 3, reads the correction data corresponding to the lens 1, and corrects the drive control parameter. Then, drive control of the lens 1 is performed using the corrected drive control parameter.
[0008]
FIG. 2 is a flowchart showing the operation of the embodiment.
In s101, it is confirmed whether or not correction data for correcting the lens drive control parameter is stored in the storage device 4. In Data1, the number of lens correction data stored is written. For example, if Data1 = 0, no correction data is stored. If the correction data is not stored, the process proceeds to s108, and the drive control parameter is not corrected.
[0009]
On the other hand, if correction data is stored, the process proceeds to s102, and the search counter i is initialized to zero. In subsequent s103, it is confirmed whether or not the value of the search counter i matches the value of Data1 indicating the number of correction data, that is, whether or not all correction data stored in the storage device 4 have been searched. When the search for all the correction data is completed, the process proceeds to step 108. In this case, it is determined that the correction data of the mounted lens 1 is not stored, and the correction of the drive control parameter is not corrected.
[0010]
If the search for all the correction data stored in the storage device 4 has not been completed, the process proceeds to s104. Data Ldata [0] input from the lens ROM 1A by the lens communication device 3 stores unique data for identifying the lens 1. Further, the storage device 4 stores correction data of one data from hosData [0] to hosData [Data1-1] for each lens identification data. hosData is 2-byte data as shown in FIG. 3, and data for identifying individual lenses is stored in the upper 1 byte. In s104, the data of Ldata [0] received from the lens 1 is compared with the upper one byte data of hosData [i], and whether hosData [i] is correction data of the lens 1 attached to the camera body 2 or not. Check out. If the data do not match, the search counter is incremented in s105 and the process returns to s102 to check the next correction data.
[0011]
If the data match, the process proceeds to s106, and the driving control parameter of the lens 1 is corrected using the lower 1 byte of hosData [i].
[0012]
Here, a driving control parameter correction method in the case where the moving subject is tracked and the lens 1 is driven and controlled will be described.
When tracking the moving subject, the lens is driven with a delay from the target position as shown in FIG. In the figure, the horizontal axis represents time, and the vertical axis represents the lens position. The target position of the lens calculated based on the focus detection data is indicated by a broken line, and the actual lens position is indicated by a solid line. As is apparent from the figure, the actual lens position is delayed from the target position. As shown in FIG. 3, the upper 4 bits of the lower 1 bytes of hosData [i] are correction values for the steady delay. That is, the correction value A is a correction value for the amount of delay that is irrelevant to the lens driving speed command value. Further, the lower 4 bits of the lower 1 byte of hosData [i] are correction values for the amount delayed in proportion to the drive speed command value.
[0013]
If the upper 4 bits of the lower 1 byte of hosData [i] are the correction value A and the lower 4 bits of the lower 1 byte of hosData [i] are the correction value B, the minimum unit for steady delay is k is corrected by A times k. For example, when k is 5 microns and A is 7, the steady delay correction value is always corrected by 5 × 7 = 35 microns. Further, the amount of delay that is proportional to the speed command value is corrected by k ′ × B microns per 1 mm / s of the image plane speed command value. For example, when k ′ = 1 and B = 4, the correction amount per 1 mm / s is 4 microns, and when the image plane speed command value is 5 mm / s, the correction amount corresponding to the speed proportional is 4 × 5 = 20. It becomes micron.
[0014]
In s107, the final correction amount is represented by the sum of the steady delay and the speed proportional component.
[Expression 1]
k × A + k ′ × B × vim
It becomes. Note that vim is an image plane speed command value. In the above example, the correction amount is
5 × 7 + 1 × 4 × 5 = 35 + 20 = 55 (micron)
It becomes.
[0015]
In the embodiment described above, an example in which correction data is searched each time a lens target position and a driving speed command value are calculated is shown. However, when the lens is replaced or when the shutter button is pressed halfway, it corresponds to each lens. It is also possible to search for correction data and store lens correction data in a memory in advance. Then, the calculation time can be shortened.
[0016]
In the configuration of the above-described embodiment, the lens 1 constitutes a lens, the storage device 4 constitutes a storage means, the lens communication device 3 constitutes an input means, and the CPU 5 constitutes a search means and a correction means.
In the above-described embodiment, the example in which the lens-specific identification data is stored in the lens ROM 1A and the identification data is input by the lens communication device 3 has been described. The identification data may be read by a reading device.
The storage device 4 may be any writable memory such as an EEPROM.
[0017]
【The invention's effect】
As described above, according to the present invention, correction data for correcting the driving control amount of the lens is additionally written in the additionally writable storage means, and the correction data is searched based on the identification data of the mounting lens, and the mounting lens. Since the drive control amount is corrected by the correction data corresponding to the above, the drive control amount can be corrected even for a new lens for which no correction data is stored. In addition, even if the lens is the same type, correction data that corrects the drive control amount to the optimum value can be written even if there are individual differences in the lens or when the lens characteristics change due to aging. Even a simple lens can always be driven with an optimal drive control amount , and drive performance can be improved.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of an embodiment.
FIG. 2 is a flowchart showing the operation of one embodiment.
FIG. 3 is a diagram for explaining a driving delay of a lens during tracking driving.
FIG. 4 is a diagram illustrating a data format of correction data.
[Explanation of symbols]
1 Lens 2 Camera body 3 Lens communication device 4 Storage device 5 CPU

Claims (3)

A lens that has lens-specific identification data and is interchangeably attached to the camera body;
Drive control means for driving and controlling the lens mounted according to a drive control amount;
Including data for correcting a steady delay of the lens and a delay proportional to the driving speed when the lens is driven while tracking a moving subject, and the drive control amount is corrected according to the mounted lens Storage means for storing correction data for writing and correction data for a new lens mounted on the camera body,
Input means for inputting the identification data;
Search means for searching correction data stored in the storage means based on identification data input by the input means, and reading correction data corresponding to the mounted lens;
Correction means for correcting the drive control amount by the correction data read by the search means,
The drive control means performs drive control on the mounted lens based on the drive control amount in which a steady delay of the lens and a delay proportional to the drive speed are corrected by the correction means. Focusing camera. The autofocus camera of claim 1,
The automatic focusing camera, wherein the unique identification data is data for identifying a lens type. The autofocus camera of claim 1,
The automatic focusing camera, wherein the unique identification data is data for identifying individual lenses of the same type of lens.

Images